1. Field of the Invention
The present invention relates to library apparatuses and drive recognition methods. More particularly, the present invention relates to a library apparatus in which a plurality of types of drive units for reading information from and writing information to an information recording medium accommodated therein are installed, and a drive recognition method used in the same.
A library apparatus houses a number of information recording mediums, such as a magnetooptical disk, and reads information from and write information to the information recording medium loaded into a drive unit.
Recently, there is an increasing demand to process large-capacity multimedia data, image data and graphic data. Correspondingly, there is an increasing need for a library apparatus capable of storing data in a large number of information recording mediums.
Various manufacturers provide various types of drive units to be housed in a library apparatus. Many improvements are being made in drive units.
As a result, a library apparatus tends to be designed to allow an extensive selection and exchanging of drive units to be housed therein. Different drive units are characterized by different insertion forces exerted when the information recording medium is inserted into the drive unit through an insertion opening; different insertion speeds; and different holding time which it takes for the recording medium to be fully introduced in the drive unit. As a result, it is necessary to control an operation of a transport device for transporting the information recording medium into the drive unit, in accordance with the type of drive unit in which the recording medium is mounted. That is, it is necessary for the transporting device to recognize the number and types of the drive units installed.
2. Description of the Prior Art
FIG. 1 is a schematic block diagram of a conventional library apparatus 1. The library apparatus 1 is connected to a host computer 2 via a Small Computer System Interface (SCSI) bus. The library apparatus performs reading and writing of data in accordance with an instruction from the host computer 2.
The library apparatus 1 comprises a medium container 4 for housing an information recording medium 3 such as a magnetooptical disk; a drive unit 5 in which the information recording medium 3 is mounted so that information is read from and written to the information recording medium; a medium transport part 6 for removing the information recording medium 3 from the medium container 4 and mounting the same in the drive unit 5 and for removing the information recording medium 3 from the drive unit 5 and housing the same in the medium container 4; a medium transport control part 7 for controlling the medium transport part 6 in accordance with a request from the host computer 2; and an operation panel 8 by which a user inputs information necessary for transport of the medium, i.e., information relating to the number and types of the drive units 5 installed in the library apparatus 1.
When a new drive unit 5 is installed in the library apparatus 1, the number of the drive units 5 installed in the library apparatus 1 changes. Therefore, it is necessary to modify the control effected by the medium transport control part 7 so that the information recording medium is delivered by the transport part 6 to the drive unit that is last mounted in the library apparatus. In case the drive unit 5 last mounted in the library apparatus 1 is from a manufacturer or of a product type different from the manufacturer or the product type of the drive units that had been installed in the library apparatus 1, a different insertion position and a different insertion force are required. It is necessary for the transport control part 7 to control the transport part 6, accordingly.
For this reason, it is necessary for the transport control part 7 to recognize the number and types of the drive units 5 installed in the library apparatus 1, whenever a new drive unit 5 is connected.
A power supply for the library apparatus 1 is turned off before the new drive unit 5 is installed therein. The drive unit 5 is then secured in a predetermined position by screws and the like. A handshake is established between a SCSI bus from the new drive unit 5 and the corresponding SCSI bus of the existing drive units and the transport control part 7. The new drive unit 5 is then connected to the host computer 2. When the power is turned on so that the library apparatus 1 is activated, information relating to the number and types of the drive units 5 already registered in an internal table 7a of the transport control part 7 is read.
By operating the operation panel 8, information specifying the number and types of the drive units 5 including the new drive unit 5 is input to the transport control part 7, thus rewriting the old information. The transport control part 7 stores the updated information in the internal table 7a.
The transport part 6 in the library apparatus 1 is controlled in accordance with the information stored in the internal table 7a of the transport control part 7.
When the host computer 2 issues to the transport control part 7 a command to move the information recording medium 3 to the drive unit, the transport control part 7 refers to the information, stored in the internal table 7a, specifying the number and types of the drive units. In accordance with the information, the transport control part 7 controls the position at which the transport part 6 holds the information recording medium 3 and also controls parameters in the insertion operation, i.e., insertion force, insertion speed and holding time.
As described above, in the conventional library apparatus, it is necessary for a user to manually input information necessary to control the transport part 6, whenever a new drive unit is connected to the library apparatus 1 or when any of the drive units is exchanged to a new one.
A failure to manually input the information or erroneous input of the information results in the transport control part failing to properly recognize the number and types of the drive units installed in the library apparatus. Thus, the information recording medium may fail to be transported to the newly mounted drive unit, or may not be mounted in the drive unit because of a difference in insertion force, insertion speed and holding time from one drive unit to another.